Water-cooled copper welding shoes presently used for Electroslag or Electrogas welding applications keep the molten weld metal and flux bath contained in the weld cavity. Water circulates through the copper shoes at a flow rate of approximately 2 gallons per minute. This flow rate is sufficient to keep the copper shoes from melting from excessive heat. In consumable-guide Electroslag or Electrogas welding, the shoes do not move. For longer joints the shoes are repositioned in a leapfrog manner, as welding continues upward. In non-consumable guide Electroslag or Electrogas welding the shoes move vertically upward with the vertical rate of rise (VRR) of the molten weld puddle.
Arcmatic® VertaSlag® Butt-Weld Water-Cooled Shoes are either cast or machined into the desired shape from pure Oxygen Free, High Conductivity pure #101Copper (OFHC-101). When machined into shape, two holes are drilled into the length of the shoe to provide an interior passage for water flow. A recess (⅛ inch deep by 1 inch wide) is machined into the front face of each shoe to shape the weld reinforcement.
Chamfered edges are provided on either side of the relieve groove where the serrated water-cooled copper shoes make contact with the parent material during the ElectroSlag or Electrogas welding process. These chamfered edges help the molten weld metal wet against the parent material, to provide complete penetration into the four corners of the weld cavity to provide and provide a smooth transition between the weld metal and the parent material. On conventional water-cooled copper shoes, each shoe has a national pipe thread (NPT) threaded hole on the input and output for connecting water circulation hose couplings. Internal threaded couplings are attached to the threaded holes and silver-soldered into position to prevent water leaks.
Two relief grooves are machined into the front face of each serrated water-cooled copper shoes, located on either side of the relief groove. These relief grooves serve to reduce the amount of surface area on the face of the serrated water-cooled copper shoe that fits tightly against the parent material. Reducing the surface area, in turn reduces the amount of heat that the serrated water-cooled copper shoe removes from the surface of the parent material. This reduction in base material heat allows the welding operator to reduce the weld voltage to dramatically decrease the size of the weld nugget and, in turn, decreases the heat input from the welding process into the work piece. This reduction in work piece heat input reduces the size of the weld nugget, and the Heat Affected Zone (“HAZ”). This reduction in overall heat input dramatically improves the physical quality of the weld. The VertaSlag® Butt-Weld Shoe is provided in two different widths: 3 inches wide and 4 inches wide (both available in a variety of lengths.
Each serrated surface of the relief groove of the Arcmatic® serrated water-cooled copper shoe serves to increase the thickness of the flux coating to the water-cooled copper shoe. This increase in flux coating serves to insulates the weld puddle from excessive cooling from the water-cooled shoes. This reduction in weld puddle cooling allows the welding operator to reduce the weld voltage to dramatically decrease the size of the weld nugget and, in turn, decreases the heat input from the welding process into the work piece. This reduction in work piece heat input further reduces the size of the weld nugget, and the HAZ.
The Arcmatic® serrated water-cooled copper shoes used in Electroslag or Electrogas welding applications require water-cooled Butt-Weld Shoes are used in pairs on either side of the welding joint. When placed against the parent material, cooling water should always enter the water-cooled copper shoe from the top access hole and exit from the bottom access hole. Water flowing from the top of the water-cooled copper shoe to the bottom of the copper shoe keeps cold water entering the shoe at all times.
Water-cooled copper shoes presently known in the art excessively cool the molten weld puddle. This over-chilling of the molten weld puddle makes it difficult for the weld puddle to melt the four corners of the weld cavity that are adjacent to the water-cooled shoes. If the molten weld puddle is not fused properly into the four corners of the weld cavity, costly weld rejects occur. To overcome this incomplete fusion into the four corners of the weld cavity, the welding operator must substantially increase the welding voltage. This excessive weld voltage increase then creates more heat input into the parent material, thus increasing the base metal dilution and the size of the HAZ.
It is, therefore, an object of the serrated water-cooled copper shoes to provide a lower welding torch voltage and still attain excellent wetting on the edges of the parent material in the weld cavity.
It is a further object of the serrated water-cooled copper shoes, used in Electroslag or Electrogas welding applications, to operate at a controlled welding shoe temperature range between of between 150 degrees Fahrenheit to 200 degrees Fahrenheit during the Electroslag or Electrogas welding operation.
It is yet another objective of the serrated water-cooled copper shoes, used in Electroslag or Electrogas welding applications, to substantially decrease the total heat input by substantially decreasing the required voltage for the Electroslag or Electrogas welding process.
Other features, advantages, and objects of the serrated water-cooled copper shoes for Electroslag or Electrogas welding applications will become apparent with reference to the following description and accompanying drawings.
These together with other objects of the serrated water-cooled copper shoes, used in Electroslag or Electrogas welding applications, along with the various features of novelty that characterize the serrated water-cooled copper shoes, are described with particularity in the claims attached to and forming a part of this disclosure. For a better understanding of the serrated water-cooled copper shoes, used in Electroslag or Electrogas welding applications, their operating advantages and the specific objects attained by their use, reference should be made to the attached drawings and descriptive materials in which there are illustrated preferred embodiments of the serrated water-cooled copper shoes.